Abstract Many individuals with Parkinson disease (PD) experience a reduction in mobility with gait difficulties that include impaired turning that can trigger freezing. These turning difficulties are particularly critical since falls during turning carry an eightfold greater risk of hip fracture compared to falls during straight line walking. Furthermore, people with PD are over three times more likely to sustain a hip fracture than age-matched cohorts without PD, and the cost of care for hip fractures in individuals with PD is approximately $192 million per year. Given the personal and economic impacts associated with falls, it is critical that we develop interventions to reduce falling risk during turning among those with PD. Mechanisms underlying impaired turning in PD are not well understood. We think that: 1) individuals with PD who have difficulty turning will show impaired ability to rapidly switch movement directions of not just the limbs but also the eyes and 2) eye movement impairments may contribute to difficulties with turning. Through use of kinematic and videooculographic analyses, along with a rotating circular treadmill and optokinetic stimulation, we will determine: 1) whether individuals with PD who have turning difficulty show impairments in ability to rapidly switch movement direction of the eyes and lower limbs, and 2) whether deficits in eye movement control contribute to turning difficulties in PD. The long-term objective of the proposed research is to better understand the relationship between oculomotor and limb motor control deficits in individuals with PD and how these deficits relate to impaired turning. Using the knowledge gained, we aim to develop innovative gait rehabilitation approaches for individuals with PD with the ultimate goal of reducing falls and hip fractures in this population.